This invention relates generally to a manually operated dispenser in the form of a trigger sprayer having an adjustable spray feature, and more particularly to such a sprayer having a composite seal, discharge valve and spin chamber forming element in which spray adjustment is made without the need to enlarge the spin chamber.
Manually operated sprayers are known to have some type of adjustable spray arrangment at the nozzle end, such that a misting element cooperates with a threaded nozzle cap which, when axially displaced, effects adjustment of the ejected spray pattern as the spin chamber depth is varied. Gradual outward displacement of the nozzle cap, as in U.S. Pat. No. 3,061,202, produces a gradually coarser spray pattern and finally an ejected stream as the spin chamber is converted into a plenum chamber. The nozzle cap may be fully tightened to effect a fine mist spray, and complete tightening to achieve a discharge shut-off. And, a separate discharge valve, resiliently urged closed by a separate spring, extends from an inner end of the misting element.
In U.S. Pat. No. 4,082,223, the discharge valve and closing spring form a one-piece element with a base plate containing radially extending and axially extending slots leading toward the discharge orifice of a threaded nozzle cap to effect a fine mist spray. An adjustable spray pattern is not provided, though a complete discharge shut-off is possible on complete tightening of the nozzle cap.
U.S. Pat. No. 1,843,411 provides for varying the capacity of a liquid fuel burner by successively closing one or more atomizer ports of an atomizer element, through an external adjustment, a segmented rotatable shutter is actuated to close or open the ports leading to tangential ducts in the atomizer element. The spray capacity through the discharge orifice is thereby varied as the discharge is throttled through the discharge orifice.
It is desirable to provide an alternative to those manually operated sprayers requiring axial displacement of the nozzle cap for changing the swirl velocity to vary the liquid ejection pattern, but without enlarging the depth of the swirl chamber and thereby avoiding an unsightly gap between the nozzle cap and adjoining pump body as well as inadvertent removal of the nozzle cap while at the same time providing for a complete discharge shut-off during conditions of non-use.